Benito Valdés’s research while affiliated with University of Seville and other places

Degraded landscapes, like those from abandoned mine areas, could be restored by revegetating them with appropriate plant species, after correction for acidity and improvement by adding exogenous organic material. Application of urban wastes to large areas of derelict land helps in the sustainable development of this landscape. However, the development of plant species in these soils could require in the future the management of possible pests or diseases by pesticide applications which could also affect plant yield. Therefore, ryegrass (Lolium perenne L.) was planted in a limed soil from the mining area of Riotinto (SW Spain), using an indoor pot experiment and the effects of amendment with sewage sludge, as well as irrigation with urban wastewater on plant uptake of the insecticide thiacloprid and the fungicide fenarimol were examined. Ryegrass biomass was reduced up to 3-fold by pesticide application. Fenarimol residues were the highest in soil, while those of thiacloprid were lower in soil and higher in ryegrass. Addition of sewage sludge and irrigation with wastewater led to a reduction of pesticide translocation to the aerial plant parts, representing a lower hazard to ryegrass quality grown in this mine soil.

Cicendia filiformis (L.) Delarbre and Exaculum pusillum (Lam.) Caruel, the two Euro-Mediterranean Gentianaceae species with the smallest and slenderest stems, are typified, the former on a figure of Vaillant and the latter on a plant specimen in Lamarck's herbarium (P-LAM).

We determined the environmental correlates of vascular plant biodiversity in the Baetic-Rifan region, a plant biodiversity hotspot in the western Mediterranean. A catalog of the whole flora of Andalusia and northern Morocco, the region that includes most of the Baetic-Rifan complex, was compiled using recent comprehensive floristic catalogs. Hierarchical cluster analysis (HCA) and detrended correspondence analysis (DCA) of the different ecoregions of Andalusia and northern Morocco were conducted to determine their floristic affinities. Diversity patterns were studied further by focusing on regional endemic taxa. Endemic and nonendemic alpha diversities were regressed to several environmental variables. Finally, semi-partial regressions on distance matrices were conducted to extract the respective contributions of climatic, altitudinal, lithological, and geographical distance matrices to beta diversity in endemic and nonendemic taxa. We found that West Rifan plant assemblages had more similarities with Andalusian ecoregions than with other nearby northern Morocco ecoregions. The endemic alpha diversity was explained relatively well by the environmental variables related to summer drought and extreme temperature values. Of all the variables, geographical distance contributed by far the most to spatial turnover in species diversity in the Baetic-Rifan hotspot. In the Baetic range, elevation was the most significant driver of nonendemic species beta diversity, while lithology and elevation were the main drivers of endemic beta diversity. Despite the fact that Andalusia and northern Morocco are presently separated by the Atlantic Ocean and the Mediterranean Sea, the Baetic and Rifan mountain ranges have many floristic similarities - especially in their western ranges - due to past migration of species across the Strait of Gibraltar. Climatic variables could be shaping the spatial distribution of endemic species richness throughout the Baetic-Rifan hotspot. Determinants of spatial turnover in biodiversity in the Baetic-Rifan hotspot vary in importance between endemic and nonendemic species.

Purpose Degraded soils, such as those encountered in areas of mine activities, need to be ameliorated by liming to correct soil acidity and by addition of organic inputs to improve soil properties and fertility. Materials and methods Non-amended mine soil and soil amended with stabilized sewage sludge were incubated for 45 days. Soil physicochemical and biological indicators were periodically measured along incubation and other enzyme activities at the end of incubation. In improved soils, a study of plant development in 250-g pots was carried out with three vegetal species: tomato, rye grass and ahipa. Germination and mortality rates, biomass production and photosynthetic pigments were measured. Results and discussion Soil incubation with sewage sludge slightly increased soil pH and led to an enhancement of soil electrical conductivity, organic carbon and dehydrogenase activity, especially for the higher doses (5 and 10%). However soil respiration was more promoted with the 2% dose, pointing to a possible toxic effect of the sludge. At the end of incubation, physicochemical and biological properties were in general enhanced. Biomass production was improved in tomato and rye grass by sewage sludge addition (more at the 2% dose), whilst ahipa growth was not affected by sewage sludge treatments. Tomato mortality reached 73% with high sludge doses (10%). Conclusions According to this set of parameters, amendment with sewage sludge of a limed acid mine soil would be considered as a good strategy for soil amelioration in view of plant establishment and development.

The occurrence of diploid and tetraploid cytotypes in Thymus section Mastichina (Lamiaceae) was investigated by chromosome counting and flow cytometric measurements of DNA content. To cover the entire native distribution of the section across the Iberian Peninsula, plant material was sampled from 29 populations, representing all three taxa (Thymus albicans, T. mastichina subsp. mastichina and T. mastichina subsp. donyanae). We provide first estimates of genome size for taxa of this section. Analyses revealed the existence of new cytotypes in T. mastichina subsp. mastichina (2n = 2x = 28, 30) and confirmed the existence of previous ones (2n = 4x = 56, 58, 60). We also confirmed the presence of exclusively diploid cytotypes (2n = 2x = 30) in the southwestern Iberian endemics T. albicans and T. mastichina subsp. donyanae. We conclude that the southwestern Iberian Peninsula acted as a Pleistocene glacial refugium that may have permitted speciation processes within this section. Several hypotheses concerning these processes and the origin and distribution of the studied taxa are discussed.

To assess the ecophysiological traits and the phytoremediation potential of the endemic heather Erica andevalensis, we determined the concentrations of major and trace elements in different plant parts and in rizosphere soils from Riotinto mining district (Huelva, Spain). The results showed that E. andevalensis may grow on substrates with very high As, Cu, Fe and Pb concentrations (up to 4114, 1050, 71900 and 15614 μg/g dry weight, respectively), very low availability of macro- and micronutrients and with pH values ranging from 3.3 to 4.9. In these harsh edaphic conditions E. andevalensis selectively absorbed and translocated essential nutrients and excludes potentially phytotoxic elements, which were accumulated in the root epidermis. The concentrations of major and trace elements in E. andevalensis aerial parts from the Riotinto mining district were in the normal range for plants; likewise other Erica species it accumulated Mn and only in a very polluted site we measured leaf concentrations of As and Pb within the excessive or toxic limits for plants. Differently from previous studies, which emphasized the soil pH and bioavailability of phytotoxic elements as the main stress factors, this study showed that in the Riotinto region, E. andevalensis can tolerate wide range of pH and toxic element concentrations; the harshest environments colonized by monospecific patches of this species were characterized above all by very low availability of nutrients. The extraordinary capability to adapt to these extreme habitats made E. andevalensis a priority species to promote the phytostabilization and the development of a self-sustaining vegetative cover on Riotinto mine tailings.

Unlabelled: Samples of bitter orange (Citrus aurantium L.) fruits (epicarp and mesocarp), leaves and its fruit marmalade from sites in Seville (Andalucia, Spain) with different levels of traffic were analysed for Ba, Cd, Cu, Fe, Mn, Ni, Pb and Zn concentrations by ICP/AES. Comparative values are given from a background area. The effect of washing on metal content in epicarp and leaves was investigated. Results revealed that Ba, Fe and Mn accumulated in leaves > epicarp > mesocarp, Cu and Ni in leaves > epicarp congruent withmesocarp and Zn leaves > mesocarp > epicarp. Washing had no significant effect on epicarp metal content while it removes part of Cu, Fe and Zn deposited on leaves. Bitter orange fruits are used mainly to make marmalade; artificial contamination effects on fruit composition were investigated and the dietary intake of the elements was determined. The citrus fruits sprayed with metal solution showed a significant increase in the studied elements compared to untreated fruits. The levels of all elements studied were lower than provisional tolerable daily intake values indicating that bitter orange marmalade consumption is safe for alimentary use. Capsule: Bitter orange tree exhibit differences in metal content between fruits and leaves and fruits are safe for consumption.

Within a blueberry research program in SW Spain, five rabbiteye (Vaccinium ashei Reade) and nine southern highbush (Vaccinium corymbosum L.) commercial cultivars along with 38 hybrid plants, produced by crossing highbush and rabbiteye cultivars, were used. The differences in the fruit size and the picking scar size among the plants, and the annual differences within each plant were studied. No significant differences were found in the fruit length, width, weight and the picking scar size between the rabbiteye and the southern highbush cultivars, and neither between the cultivars and the hybrid progeny. However, significant differences were found among the cultivars and among the hybrid plants. The picking scar size correlates better with fruit width and weight than with fruit length, although correlation values are not high. Thus, outliers were observed, some of them interesting to be selected for having large fruits and narrow scars. The ratio between the picking scar and fruit width shows significant differences among subsequent years in many hybrid plants.

A synopsis of genera accepted for the Euro+Med project is presented. As a consequence of the generic treatment and reassessment of accepted specific and subspecific taxa, new names and new combinations are required in Agrostis, Alopecurus, Anisantha, Arundo, Avellinia, Avenella, Avenula, Bromopsis, Bromus, Danthonia, Elymus, Elytrigia, Enneapogon, Eragrostis, Koeleria, Macrochloa, Neoschischkinia, Ochlopoa, Phalaroides, Rostraria, Secale, Setaria, Stipa, Triticum and Urochloa. The genus name Tripidium is validated to substitute the illegitimate Ripidium.